The property possessed by some materials of improving detergency levels of soaps and synthetic detergents and the use of such materials in detergent compositions is known. Such cleaning boosters are called "builders." Builders permit the attainment of superior cleaning performance both as regards quality of finished work and lower cost, than is possible when so-called unbuilt compositions are used.
The behavior and mechanism by which builders perform their function is not fully understood although several explanations for their behavior are available. Nevertheless, an unequivocal criterion does not exist which would permit one to predict accurately which class of compounds possess valuable builder properties and which compounds do not.
This may be explained in part by the complex nature of detergency and the countless factors which contribute to overall performance results. Builder compounds have been found to have some effect, for instance, in such areas as stabilization of solid soil suspension, emulsification of soil particles, the surface activity of aqueous detergent solutions, solubilization of water-insoluble materials, foaming or suds producing characteristics of the washing solution, peptization of soil agglomerates, neutralization of acid soil, and the inactivation of mineral constituents present in the washing solution. Thus, any theoretical discussion of the boosting capacity of a builder compound should give due consideration to all the significant individual actions involved in the detergent process and must apply equally to all usual conditions of soiling and washing.
Examples of know builder materials are water-soluble inorganic alkaline builder salts which can be used alone or in combination, including alkali metal carbonates, borates, phosphates, bicarbonates and silicates. Examples of know organic builder materials are alkali metal, ammonium or substituted ammonium aminopolycarboxylates, e.g. sodium and potassium ethylenediaminetetraacetate, sodium and potassium N(2-hydroxyethyl)-ethylenediaminetriacetate, sodium and potassium and triethanolammonium-N-(2-hydroxyethyl)-nitrilodiacetate. Alkali metal salts of phytic acid, e.g. sodium phytate, are also suitable as organic builders.